In our above-identified application, we disclosed how the addition of saturated rubbers; for example, ethylenepropylene copolymers or hydrogenated polyisoprene, modified by grafting acrylates thereto, could when added to polymethylmethacrylate or other acrylates provide weatherable, impact resistant polyacrylate products.
Many polymers, such as polycarbonates, used in engineering applications are tough, but difficult to process and expensive. It is desirable that such high cost polymers be extended without reducing their toughness by blending them with less expensive polymers, and also to increase their processability.
According to the prior art, the brittleness of polycarbonate in thick sections may be reduced by the addition of a modified rubber composition.
U.S. Pat. No. 4,419,491 entitled THERMOPLASTIC RESIN COMPOSITION EXCELLENT IN COLOR DEVELOPMENT, issued Dec. 6, 1983 to Sakano et al discloses blends of styrene acrylonitrile (SAN) modified EPDM, SAN copolymers, methylmethacrylate polymers, and polycarbonate resin blends. We have discovered that the use of acrylonitrile, a nitrogenous acrylate, produces much inferior results than blends where the EPDM is modified with a non-nitrogenous acrylate.
We have further discovered that polycarbonates extended with a modified polymer graft rubber compositions, such as disclosed in U.S. Pat. No. 4,456,725, issued Jun. 26, 1984 to Liu et al entitled COMPOSITIONS COMPRISING POLYCARBONATES, ACRYLATE RESINS, AND ALIPHATIC HYDROCARBONS, and in U.S. Pat. No. 4,638,033, issued Jan. 20, 1987 to Boutni et al entitled RESINOUS COMPOSITION OF A CARBONATE RESIN AND A GRAFTED DERIVATIVE OF ETHYLENEPROPYLENE-DIENE TERPOLYMER EXHIBITING IMPROVED RESISTANCE TO ORGANIC SOLVENTS, utilizing nitrogenous acrylates in the blends did not exhibit the high strength qualities of the blends we have discovered comprising a non-nitrogenous polyacrylate polymer.